1. Field of the Invention
The present invention concerns a device for measuring the composition of a liquid contained in a multi-phase mixture, particularly suited to be used in the sector of oil extraction.
2. Present State of the Art
As is known, in the oil field there is the need to determine the composition of the multi-phase mixtures extracted from the wells, which are commonly constituted by a liquid phase, comprising oil, water and other components, if any, and by a gas phase.
One of the operations that are commonly performed to determine the characteristics of the mixture consists in measuring the composition of the liquid phase and, in particular, the water volume concentration with respect to the entire quantity of liquid commonly known as “water-cut” and the concentration of other types of liquid, with the aid of suitable probes including, for example, the well-known NIR (Near Infrared) probes, which exploit the principle of the attenuation of an infrared light beam that passes through the liquid.
These probes are inserted in the duct into which the mixture flows, so that they are hit by the flow of the mixture itself.
In the known systems, the reliability and precision of the concentration measure that can be obtained decrease with the increase of the volume percentage of the gas phase, commonly known as “gas-volume fraction” (GVF), meaning that the measure becomes less reliable and precise as the volume percentage of liquid contained in the mixture decreases.
In fact, as the GVF increases, the liquid tends to be progressively dispersed in drops that are more or less insulated within the gas flow.
Consequently, the probe is hit by said drops in a discontinuous way and this makes it difficult to carry out a reliable and precise measurement of the composition.